Chongyang Jiang

The automation and continuous operation of coal production are fundamental to the construction of high-yielding and efficient mines. Underground coal bunkers, serving as the pivotal link between various production and transportation segments, are vital for the seamless operation of mines. Nonetheless, the adhesive properties of raw coal can lead to increasingly severe issues, such as the adhesive clogging of coal bunkers. To address this issue, this paper first employs a self-designed raw coal shear testing apparatus to conduct experiments under varying conditions of shear interfaces, moisture content in raw coal, and compaction forces. Obtaining the adhesion behavior characteristics and adhesion parameter variation patterns of raw coal at coal-coal and coal-wall interfaces under various influencing factors. Subsequently, leveraging the adhesion property parameters of raw coal and the engineering conditions of the 1011 roadway coal bunker in Taoyuan Coal Mine II, a numerical model for coal bunker discharge using irregular particles was developed with the PFC2D numerical simulation software. Based on these, we obtained the influence patterns of various factors, such as coal bunker convergence angle, coal storage height, and coal moisture content, on the coal particle flow pattern, bunker wall pressure, and adhesive clogging distribution characteristics of the coal bunker during the discharge process, thereby revealing the mechanisms underlying the adhesive clogging phenomenon. The findings offer significant insights for optimizing solutions to the adhesive clogging issues in underground coal bunkers and ensuring their safe and efficient operation.

Taking the roadway peripheral rock anchoring unit as the research object, the rock compression test containing the anchor solid was carried out to analyze the influence of the degree of peripheral rock fragmentation and the anchor support method on the mechanical properties of the rock body. The test results showed that the smaller the size of the structural surface, the more a greater number of anchor rods were needed, which in turn provided better support. With the increase in the size of the structural surface, the uniaxial compressive strength and modulus of elasticity of the specimen showed a gradual decrease. Numerical tests of the uniaxial compression of rock containing cohesive units showed that the deformation of the specimen near the anchor bar was significantly reduced, while the main rupture surface was blocked, and an obvious reinforcement zone was formed near the anchor bar. Under the double-anchor condition, the anchor tension stress was more obvious, the reinforcement zone was wider, and the rock rupture surface was strongly blocked, all of which made its reinforcement effect the more obvious. This double-anchor condition showed that the anchoring effect of the anchor rods on the specimens was reflected in two aspects of reinforcement and crack stopping. The denser the anchor rods, the wider the reinforcement zone and hence the more likely that the superposition effect will occur, which allowed the anchor rods to play a greater supporting role in stabilizing the rock. The research results can provide a theoretical basis for the design of anchor support and early warning prediction of destabilization damage in the fractured surrounding rock of coal mine roadways.

Affected by mining stress, roadways surrounding rock face problems such as serious deformation and failure and difficult support. In this study, with the II2 mining area rise in Taoyuan Coal Mine taken as the engineering background, the evolution laws of stress, deformation and plastic zone area of the mining area rises during the advance process of the working face were explored with the aid of FLAC^3D software. The results suggested that the stress, deformation and plastic zone area of the surrounding rock increase significantly when the distance between the working face and the track rise is less than 20 m. Based on this finding, it was further determined that the stopping line of the II8₂22 working face should be at least 20 m away from the track rise. Furthermore, in accordance with the deformation and failure characteristics of surrounding rock under the influence of mining stress, this paper conducted a simulation on four support schemes of mining area rises, and quantitatively analyzed the mechanical response of a roadway surrounding rock under these support schemes. The simulation results revealed that the support scheme of “bolt-mesh-spray-cable + grouting bolt” can effectively deal with the influence of mining stress on the working face. Meanwhile, an engineering application was carried out. By monitoring the surface displacement of the surrounding rock, it was found that the deformation of the roadway surrounding rock was effectively controlled, and a remarkable support effect was achieved. In short, the proposed support scheme greatly improved the stability and safety of surrounding rock in the mining area rise under the influence of mining stress.